Early films Sistiaga exhibited his first film in 1968 at the Bilbao Short Film Festival. Titled ... ere erera baleibu izik subua aruaren ... (a nonsense phrase coined by Sistiaga's friend Rafael Ruiz Balerdi), it won a prize for best experimental film. This 10-minute short, hand-painted in a fairly conventional cartoon style, was later renamed De la Luna a Euskadi ('From the Moon to the Basque').

The artist began painting his abstract magnum opus in 1968. It took 17 months of 10-12 hour days to complete. The silent, 75-minute ... ere erera baleibu izik subua aruaren ... was first exhibited at Madrid in 1970. Subsequent screenings took place in London, Paris, Barcelona and New York City.

Each of the approximately 108,000 frames in ... ere erera is completely unique, and appears onscreen for only 1/24th of a second. No optical printing techniques or special photographic effects were employed in its production.

... ere erera baleibu izik subua aruaren ... is the first feature-length example of 'direct' cameraless filmmaking, a painstaking technique dating back to the early 1900s. Other well-known artists in the genre include Len Lye, Harry Smith, Norman McLaren (whose work Sistiaga cites as a direct influence) and Stan Brakhage.

Later hand-painted films In 1988-89, Sistiaga painted Impresiones en la alta atmósfera ('Impressions from the Upper Atmosphere') in 70mm 15-perf horizontal format, intended for exhibition in giant-screen IMAX and theaters. A new work in the same format, Han (sobre el sol) ('Han (About the Sun)') was begun in 1992.